IQ gap among races

The modern controversy surrounding intelligence and race focuses on the results of IQ studies conducted during the second half of the 20th century in the United States, Western Europe, and other industrialized nations. In almost every testing situation where the tests were administered and evaluated correctly, a difference of approximately one standard deviation was observed between the mean IQ score of blacks and whites. In the United States, the mean IQ score among blacks is approximately 85 and the mean IQ score among whites is approximately 100; the mean IQ score of Hispanics is usually reported to be between the mean black and white scores. The mean score for people of East Asian and Jewish descent is usually higher than the mean score of whites, but the extent of that difference is not precisely known. However, several studies place the median IQ of Ashkenazi Jews (who make up the overwhelming majority of American Jews) at approximately one standard deviation above the mean for other whites. In a normal distribution, only about 16% of the population is at least one standard deviation above the mean.

Similar gaps are seen in other tests of cognitive ability or aptitude, including the SAT. Likewise, the gap is reflected by gaps in the academic, economic, and social factors correlated with IQ. The practical importance of intelligence makes the source and meaning of the IQ gap a pressing social concern.

Many compilations of average IQ by country place East Asian countries at the top of such lists. Some argue that this is in part attributed to some IQ tests' inherent bias towards testing spatial reasoning. They argue that logographic languages like Chinese or Japanese develop spatial reasoning better than Roman languages prevalent in Europe and America. The same reasoning has been used to explain why students from Asia-Pacific countries (eg Singapore, South Korea) tend to score better than average in tests of mathematics. Some argue that the East Asian advantage can also be explained by more rigorous education programs. Opponents of these interpretations point out that people of East Asian descent who are born and educated in the United States and primarily speak English have a higher mean IQ score than their white peers.

Arthur Jensen was one of the first researchers to propose that the IQ gap between blacks and whites is best explained by a hypothesis that attributes at least some of the cause to genetic factors. His 1969 paper in "Harvard Education Review" also stated that compensatory education was not very effective and that "genetic differences were more important than cultural or socioeconomic differences in explaining individual differences in IQ within the white population."

In 1974, an English biologist named John Randal Baker presented a lengthy argument in favor of innate racial differences in intelligence in a volume entitled "Race" (Oxford University Press, 1974), in which he claimed there had been a systematic, politically motivated suppression of classical biological anthropology outside Germany since the 1930s, and went on to attempt to demonstrate a relation among five historical civilizations (Sumerian, Egyptian, Indus valley, Helladic-Minoan and Sinic) and the supposed biological dispositions of their creators.

Reaction time and IQ

In 1991,

Richard Lynn tested 1,468 9-year old children consisting of Blacks from South Africa, East Asians from Hong Kong and Japan, and Whites from Britain and Ireland. The content of the tests involved flipping a switch after one or more lights came on. Lynn found that the decision times (the time taken to make a decision about what to do) correlated with IQ data on Raven Progressive Matrices tests also administered during the same study, although movement times (the time taken to execute the decision) did not. He found that the Asians had the fastest decision times, followed by the Whites, and then by the Blacks. He also determined that the Black children had movement times that were substantially faster than those of Whites and Asians on certain tests.

Means for Progressive Matrices and 12 reaction time measures for 9 year old children from five countries (in milliseconds).

Hong Kong

Japan

Britain

Ireland

South Africa

SD

r

Number

118

444

239

317

350

Progressive Matrices IQ

113

110

100

89

67

Decision time

Simple

361

348

371

388

398

64

-93**

Complex

423

433

480

485

489

67

-83*

omo

787

818

898

902

924

187

-86**

Movement Time

Simple

273

218

236

260

236

72

13

Complex

267

227

261

280

236

66

13

omo

323

268

297

307

256

96

56

Decision Time Variabilities

Simple

99

103

90

121

129

32

-83*

Complex

114

138

110

141

155

30

-73

omo

269

298

285

328

332

95

-85*

Movement Time Variabilities

Simple

68

63

52

73

69

30

-33

Complex

65

66

56

80

70

25

-42

omo

136

127

110

129

119

49

40

One and two asterisks denote statistical significance at the 5 and 1 per cent level, respectively.